How to Make Bougainvillea Bloom
When bougainvilleas are blooming well, they produce a dazzling shower of color. But it is not always easy to persuade this tropical climber to bloom in temperate climates. With a little attention and a lot of summer sun, though, you can stimulate a riot of bright colors that will be the highlight of your garden. Bougainvilleas are a climbing vine with sharp thorns on the long woody stems. The flowers come in a variety of colors from pinks and reds to purple, orange and white.
Plant Bougainvillea in large pots. Twenty- to 30-inch pots work best and are still movable. In order to bloom, bougainvillea likes to have a crowded root system, which is easier to do in a pot than in the ground.
Place pots in full sun throughout the summer. Bougainvilleas are a tropical plants that need plenty of sun to bloom. If you keep your bougainvillea in the shade or against a high wall, it is unlikely to produce blossoms.
In the fall cut back bougainvillea heavily. You can take off up to half the plant, or 20 to 30 inches on a plant that is 4 to 6 feet tall. Bougainvilleas bloom on the green wood at the tips of long tendril-like limbs. Cutting back a bougainvillea heavily in the fall will stimulate the production of new green wood in the spring. This will stimulate the bougainvillea to bloom as the summer heats up and more sun is available.
Bring plants indoors over the winter if there is a chance of frost. Bougainvilleas are tropical plants that are frost sensitive. Allow plants to go dormant over the winter, mild watering every few weeks is enough to keep the plant alive without stimulating premature growth.
After the threat of frost has passed move bougainvilleas outdoors. Place in the sunniest spots in your garden for maximum blooming activity.
Fertilize once a week using 1 to 2 cups of hibiscus plant food (12-4-18), which can be purchased at the nursery or garden store.
Water every other day letting the soil around your bougainvilleas dry out in between. Check the soil before watering; if it still feels damp to the touch, put off watering until another day. Make sure the pots have drainage holes in the bottom so that water does not sit around the roots and cause them to rot.